NumberResearch Membership · Data 09/20/2026

Recent prefix assignments

0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/20/2026

Full prefixes (NXX) Thousands-blocks (1,000-number pools)

The Code holder is who opened each NPA-NXX prefix — not necessarily who holds the numbers. A prefix is 10,000 numbers, but under pooling its ten 1,000-number blocks are handed out individually, often to different carriers; the code holder may hold only one block, or none. The Thousands-blocks column shows how the ten blocks are really split — click which blocks → to see who holds each 1,000-number block and its last-4-digit range. Assignments are initial assignments; the current serving carrier may differ due to portability.

Most active assignees, all time — NPA 603
LEVEL 3 COMMUNICATIONS, LLC - NH 37
New assignments by month Sep 2026 Aug 2026 Jul 2026 Jun 2026 May 2026 Apr 2026 Mar 2026 Feb 2026 Jan 2026 Dec 2025 Nov 2025 Oct 2025
Clear Download CSV ↓
Recent NPA-NXX prefix assignments
AssignedNPA-NXXThousands-blocks taken (last-4 opening)Code holderOCNRate centerState
2004-08-17 603-709 0XXX2XXX3XXX4XXX5XXX6XXX7XXX8XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 PLAINFIELD NH
2001-07-11 603-301 0XXX1XXX4XXX5XXX6XXX8XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 CTROSSIPEE NH
— 603-259 0XXX1XXX2XXX3XXX6XXX7XXX8XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 LITTLETON NH
— 603-280 0XXX1XXX3XXX6XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 BARRINGTON NH
— 603-287 0XXX1XXX2XXX3XXX5XXX7XXX8XXX9XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 CLAREMONT NH
— 603-294 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 PORTSMOUTH NH
— 603-326 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 BERLIN NH
— 603-331 0XXX1XXX2XXX3XXX5XXX6XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 COLEBROOK NH
— 603-369 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 CONCORD NH
— 603-379 0XXX1XXX2XXX3XXX5XXX6XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 RYE BEACH NH
— 603-499 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 KEENE NH
— 603-556 0XXX1XXX2XXX3XXX5XXX7XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 LACONIA NH
— 603-565 0XXX1XXX2XXX3XXX5XXX9XXX · 6 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 PENACOOK NH
— 603-567 0XXX7XXX8XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 PETERBROGH NH
— 603-574 0XXX which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 ALSTEAD NH
— 603-576 2XXX which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 ORFORD NH
— 603-583 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 EXETER NH
— 603-614 2XXX3XXX5XXX6XXX8XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 WCHESTEFLD NH
— 603-618 none assigned yet which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 PIKE NH
— 603-678 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 LEBANON NH
— 603-684 0XXX1XXX2XXX3XXX6XXX8XXX9XXX · 7 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 LANCASTER NH
— 603-725 0XXX6XXX · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 TAMWORTH NH
— 603-728 1XXX2XXX3XXX5XXX7XXX8XXX9XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 NOWOODSTOK NH
— 603-733 2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 NO CONWAY NH
— 603-741 4XXX5XXX7XXX8XXX · 4 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 NEW BOSTON NH
— 603-769 0XXX1XXX3XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 MILFORD NH
— 603-780 none assigned yet which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 CANAAN NH
— 603-782 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 5 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 MANCHESTER NH
— 603-819 0XXX1XXX3XXX5XXX6XXX8XXX9XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 PLAISTOW NH
— 603-871 3XXX8XXX · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 SANBORNVL NH
— 603-873 0XXX8XXX · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 SUNAPEE NH
— 603-874 1XXX which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 MONROE NH
— 603-923 0XXX1XXX2XXX3XXX5XXX7XXX8XXX9XXX · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 ROCHESTER NH
— 603-951 0XXX2XXX · 2 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 MILAN NH
— 603-952 0XXX1XXX2XXX3XXX5XXX6XXX7XXX8XXX9XXX · 3 holders which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 SALEM NH
— 603-967 8XXX which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 HAMPTON NH
— 603-992 2XXX which blocks → LEVEL 3 COMMUNICATIONS, LLC - NH 4017 DANBURY NH

Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/20/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.